Relationships Between Personal Exposure to Heat and Cold and Air Pollutants

Abstract

PP-30-082 Background/Aims: The adverse health effects associated with climate change have been well studied. However, because personal activity patterns could change with changing climate, personal exposure to ambient pollution would also change, thereby modifying these health effects. Time activity patterns and ambient concentrations of air pollutants determine the direct exposure to ambient air pollutants. People spend different amounts of time outdoors depending on the weather. In response to temperature changes, people use climate control systems in indoor environments, which in turn, modify the infiltration of air pollutants; in vehicles, people roll windows up or down, or turn on the air conditioner or heater, which in turn determines their exposure to on-road vehicle exhaust. The associations between personal exposure to heat and cold and to air pollutants are investigated in this study. Methods: Personal activity information and residential household characteristics were obtained from questionnaires from the RIOPA study for homes in Elizabeth (NJ), Los Angeles (CA), and Houston (TX). The 48-hours average indoor and outdoor temperatures and air exchange rate were measured for each home. Meteorological parameters, including maximum daily temperature (Tmax) and relative humidity, were obtained from the nearest airport; data for ambient ozone and particulate matter (PM2.5) concentrations were taken from the Environmental Protection Agency's Air Quality System. Results: Statistically significant associations between ambient temperature and the time fraction people spent in various microenvironments were observed with Beta regressions. Heat and cold exposure was significantly associated with microenvironmental ventilation, using air conditioners or heating systems in indoor environments, and turning on air conditioners in vehicles. Personal exposures to ambient PM2.5 and O3 and to heat and cold were characterized with LOESS for subpopulations in each city. Conclusion: In most cases, temperature is a significant predictor for personal activity patterns. Associations with air pollutants will also be presented.